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Homework Help: Last part of question on continuous functions

  1. Apr 20, 2010 #1
    1. The problem statement, all variables and given/known data
    This is the last part of a revision question I'm trying, would really like to get to the end so any pointers or help would be greatly appreciated.

    Suppose h:(0,1)-> satisfies the following conditions:
    for all xЭ(0,1) there exists d>0 s.t. for all x'Э(x, x+d)n(0,1) we have h(x)<=h(x')

    Prove that if h is continuous on (0,1) then h(x)<=h(y) whenever x.yЭ(0,1) and x<=y. Use a counterexample to show that this results may not be true when h is continuous.

    2. Relevant equations
    Well, definition of continuous functions,
    also above in the question i am asked to state the intermediate value theorem so i think perhaps i am meant to use that.

    3. The attempt at a solution

    if h is continuous on (0,1) then for all cЭ(0,1), for all E>0, Эd s.t. for all xЭ(0,1), 0<|x-c|<d this implies that |h(x)-h(c)|<E
    i really just don't see how to continue. Any help would be great. Thank you
  2. jcsd
  3. Apr 20, 2010 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    Try fixing x, and showing that for every value of y larger than it, h(x)<=h(y)
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